The report did not specify how far advanced the proceedings were. Xinhua said it had learned of the charges today.

Prosecutors for the Hefei Municipal Procuratorate in Anhui province have questioned the two defendants and consulted their defense team, Xinhua stated.

Reuters cited one of the lawyers as saying that the trial was due to begin on August 7-8.

Heywood was found dead last November in a hotel room in Chongqing, where Bo Xilai was regional head of the Communist Party.

City authorities – who Bo effectively commanded at the time – originally attributed Heywood’s death to alcohol poisoning, and cremated his body without an autopsy.

Reports subsequently emerged of a cover-up. Bo was abruptly sacked in March, shortly after his police chief sought asylum in the US consulate, reportedly after a dispute with the party leader.

Then, in April, Gu was detained in connection with a new investigation into Heywood’s death.

Xinhua said at the time that Gu had fallen out with Heywood “over economic interests, which had been intensified.” Last month, Japanese media reported that Gu had confessed to poisoning the businessman in order to prevent him revealing that he had helped her organize illegal foreign money transfers worth billions of dollars.

According to Xinhua, Gu was also concerned that Heywood might endanger her son, the BBC said. The Brit is reported to have acted as a mentor to 24-year-old Bo Guagua.

Bo Xilai has not so far been cited in the homicide case. He is currently under investigation for violating Communist Party rules.